A trireme ( ; ; cf. ) was an ancient vessel and a type of galley that was used by the ancient maritime civilizations of the Mediterranean Sea, especially the Phoenicians, ancient Greeks and Romans.

The trireme derives its name from its three rows of oars, manned with one man per oar. The early trireme was a development of the penteconter, an ancient warship with a single row of 25 oars on each side (i.e., a single-banked boat), and of the bireme (, ), a warship with two banks of oars, of Phoenician origin.Casson (1995), pp. 57–58 The word dieres does not appear until the Roman period. According to Morrison and Williams, "It must be assumed the term pentekontor covered the two-level type".Morrison and Williams 1968:155 As a ship, it was fast and agile and was the dominant warship in the Mediterranean from the 7th to the 4th centuries BC, after which it was largely superseded by the larger quadriremes and quinqueremes. Triremes played a vital role in the Persian Wars, the creation of the Athenian maritime empire and its downfall during the Peloponnesian War.

Medieval and early modern galleys with three files of oarsmen per side are sometimes referred to as triremes.See index in Morrison (2004) for examples.

History

Origins

Depictions of two-banked ships (biremes), with or without the parexeiresia (the outriggers, see below), are common in 8th century BC and later vases and pottery fragments, and it is at the end of that century that the first references to three-banked ships are found. Fragments from an 8th-century relief at the Assyrian capital of Nineveh depicting the fleets of Tyre and Sidon show ships with rams, and fitted with oars pivoted at two levels. They have been interpreted as two-decked warships, and also as triremes.Morrison 1995: 146

Modern scholarship is divided on the provenance of the trireme, Greece or Phoenicia, and the exact time it developed into the foremost ancient fighting ship.Anthony J. Papalas (1997): "The Development of the Trireme", The Mariner's Mirror, Vol. 83, No. 3, pp. 259–271 (259f.) According to Thucydides, the trireme was introduced to Greece by the Corinthians in the late 8th century BC, and the Corinthian Ameinocles built four such ships for the Samians.Thucydides I.13.2–5 This was interpreted by later writers, Pliny and Diodorus, to mean that triremes were invented in Corinth.Diodorus, Bibliotheca historica, XIV.42.3 Clement of Alexandria in the 2nd century, drawing on earlier works, explicitly attributes the invention of the trireme (trikrotos naus, "three-banked ship") to the SidoniansStromata, I 16.36 the possibility remains that the earliest three-banked warships originated in Phoenicia.

Early use and development

Herodotus mentions that the Egyptian pharaoh Necho II (610–595 BC) built triremes on the Nile, for service in the Mediterranean, and in the Red Sea, but this reference is disputed by modern historians, and attributed to a confusion, since "triērēs" was by the 5th century used in the generic sense of "warship", regardless its type.The Age of the Galley, pp. 45–46 The first definite reference to the use of triremes in naval combat dates to , when, according to Herodotus, the tyrant Polycrates of Samos was able to contribute 40 triremes to a Persian invasion of Egypt (Battle of Pelusium).Herodotus, III.44 The Persians were the first nation to use triremes in significant numbers. By 490 BC, triremes were the backbone of the Persian fleet. Thucydides clearly states that in the time of the Persian Wars, the majority of the Greek navies consisted of (probably two-tiered) penteconters and ploia makrá ("long ships").Thucydides I.14.1–3

In any case, by the early 5th century, the trireme was becoming the dominant warship type of the eastern Mediterranean, with minor differences between the "Greek" and "Phoenician" types, as literary references and depictions of the ships on coins make clear. The first large-scale naval battle where triremes participated was the Battle of Lade during the Ionian Revolt, where the combined fleets of the Greek Ionian cities were defeated by the Persian fleet, composed of squadrons from their Phoenician, Carian, and Egyptian subjects.

The Persian Wars

Athens was at that time embroiled in a conflict with the neighbouring island of Aegina, which possessed a formidable navy. In order to counter this, and possibly with an eye already at the mounting Persian preparations, in 483/2 BC the Athenian statesman Themistocles used his political skills and influence to persuade the Athenian assembly to start the construction of 200 triremes, using the income of the newly discovered silver mines at Laurion. The first clash with the Persian navy was at the Battle of Artemisium, where both sides suffered great casualties. However, the decisive naval clash occurred at Salamis, where Xerxes' invasion fleet was decisively defeated.

After Salamis and another Greek victory over the Persian fleet at Mycale, the Ionian cities were freed, and the Delian League was formed under the aegis of Athens. Gradually, the predominance of Athens turned the League effectively into an Athenian Empire. The source and foundation of Athens' power was her strong fleet, composed of over 200 triremes. It not only secured control of the Aegean Sea and the loyalty of her allies, but also safeguarded the trade routes and the grain shipments from the Black Sea, which fed the city's burgeoning population. In addition, as it provided permanent employment for the city's poorer citizens, the fleet played an important role in maintaining and promoting the radical Athenian form of democracy. Athenian maritime power is the first example of thalassocracy in world history. Aside from Athens, other major naval powers of the era included Syracuse, Corfu and Corinth.

In the subsequent Peloponnesian War, naval battles fought by triremes were crucial in the power balance between Athens and Sparta. Despite numerous land engagements, Athens was finally defeated through the destruction of her fleet during the Sicilian Expedition, and finally, at the Battle of Aegospotami, at the hands of Sparta and her allies.

Design

Based on all archeological evidence, the design of the trireme most likely pushed the technological limits of the ancient world. After gathering the proper timbers and materials it was time to consider the fundamentals of the trireme design. These fundamentals included accommodations, propulsion, weight and waterline, centre of gravity and stability, strength, and feasibility. All of these variables are dependent on one another; however a certain area may be more important than another depending on the purpose of the ship.

The arrangement and number of oarsmen is the first deciding factor in the size of the ship. For a ship to travel at high speeds would require a high oar-gearing, which is the ratio between the outboard length of an oar and the inboard length; it is this arrangement of the oars which is unique and highly effective for the trireme. The ports would house the oarsmen with a minimal waste of space. There would be three files of oarsmen on each side tightly but workably packed by placing each man outboard of, and in height overlapping, the one below, provided that thalamian tholes were set inboard and their ports enlarged to allow oar movement. Thalamian, zygian, and thranite are the English terms for (), (), and (), the Greek words for the oarsmen in, respectively the lowest, middle, and uppermost files of the triereis. The tholes were pins that acted as fulcrums to the oars that allowed them to move. The center of gravity of the ship is low because of the overlapping formation of the files that allow the ports to remain closer to the ships walls. A lower center of gravity would provide adequate stability.

The trireme was constructed to maximize all traits of the ship to the point where if any changes were made the design would be compromised. Speed was maximized to the point where any less weight would have resulted in considerable losses to the ship's integrity. The center of gravity was placed at the lowest possible position where the Thalamian tholes were just above the waterline which retained the ship's resistance to waves and the possible rollover. If the center of gravity were placed any higher, the additional beams needed to restore stability would have resulted in the exclusion of the Thalamian tholes due to the reduced hull space. The purpose of the area just below the center of gravity and the waterline known as the () was to allow bending of the hull when faced with up to 90 kN of force. The calculations of forces that could have been absorbed by the ship are arguable because there is not enough evidence to confirm the exact process of jointing used in ancient times. In a modern reconstruction of the ship, a polysulphide sealant was used to compare to the caulking that evidence suggests was used; however this is also contentious because there is simply not enough evidence to authentically reproduce the triereis seams.

Triremes required a great deal of upkeep in order to stay afloat, as references to the replacement of ropes, sails, rudders, oars and masts in the middle of campaigns suggest.Hanson (2006), p. 260Fields (2007), p. 10 They also would become waterlogged if left in the sea for too long. In order to prevent this from happening, ships would have to be pulled from the water during the night. The use of lightwoods meant that the ship could be carried ashore by as few as 140 men.IG I.153 Beaching the ships at night, however, would leave the troops vulnerable to surprise attacks. While well-maintained triremes would last up to 25 years, during the Peloponnesian War, Athens had to build nearly 20 triremes a year to maintain their fleet of 300.

The Athenian trireme had two great cables of about 47 mm in diameter and twice the ship's length called hypozomata (undergirding), and carried two spares. They were possibly rigged fore and aft from end to end along the middle line of the hull just under the main beams and tensioned to 13.5 tonnes force. The hypozomata were considered important and secret: their export from Athens was a capital offense. This cable would act as a stretched tendon straight down the middle of the hull, and would have prevented hogging. Additionally, hull plank butts would remain in compression in all but the most severe sea conditions, reducing working of joints and consequent leakage. The hypozomata would also have significantly braced the structure of the trireme against the stresses of ramming, giving it an important advantage in combat. According to material scientist J.E. Gordon: "The hupozoma was therefore an essential part of the hulls of these ships; they were unable to fight, or even to go to sea at all, without it. Just as it used to be the practice to disarm modern warships by removing the breech-blocks from the guns, so, in classical times, disarmament commissioners used to disarm triremes by removing the hupozomata."

Dimensions